1. Technical Field of the Invention
The present invention relates to novel cosmetic and/or dermatological compositions (referred to hereinbelow as sunscreen compositions) intended for protecting the skin and/or the hair against the deleterious effects of UV radiation, in particular, solar radiation. More specifically, the invention relates to novel cosmetic and/or dermatological compositions with enhanced photostability and comprising, in a cosmetically and/or dermatologically acceptable support, a combination of at least three specific UV-screening agents.
This invention also relates to the use of photoprotecting compositions in the cosmetic and/or dermatological fields.
2. Description of the Prior Art
It is known to this art that light radiation of wavelengths of from 280 nm to 400 nm permits tanning of the human epidermis, and that light radiation with wavelengths, more particularly, of from 280 to 320 nm, i.e., UV-B irradiation, causes skin burning and erythema which can impair the development of a natural tan. For these reasons, as well as for aesthetic reasons, there is an increasingly constant demand for a means of controlling this natural tanning in order to thereby control the color of the skin. This UV-B radiation must be screened from the skin.
It is also known to this art that UV-A radiation, of wavelengths of from 320 to 400 nm, which tan the skin, also adversely affects it, especially in the case of sensitive skin or skin which is continually exposed to solar radiation. UV-A rays especially cause a loss in the elasticity of the skin and the appearance of wrinkles, thereby promoting premature skin aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals, they may even be the cause of phototoxic or photoallergic reactions. Thus, for aesthetic and cosmetic reasons, such as conservation of the natural elasticity of the skin, for example, an ever-increasing number of people wish to control the effect of UV-A rays on their skin, it is therefor desirable also to screen out UV-A radiation.
Thus, with the aim of providing protection for the skin and the hair against UV radiation as a whole, this protection being as full and as effective as possible, combinations of screening agents which are active in the UV-A range and of screening agents which are active in the UV-B range are generally used in the manufacture of sunscreen compositions.
In this respect, a particularly advantageous set of UV-A screening agents currently include the dibenzoylmethane derivatives and, in particular, 4-tert-butyl-4'-methoxydibenzoylmethane, which effectively have a high intrinsic power of absorption. These dibenzoylmethane derivatives, which are now products that are well known in the art as sunscreen agents that are active in the UV-A range, are described in particular in FR-A-2,326,405 and FR-A-2,440,933, as well as in EP-A-0,114,607. 4-(Tert-butyl)-4'-methoxydibenzoylmethane is currently sold under the trademark "Parsol 1789" by Givaudan.
Similarly, 1,3,5-triazine derivatives and, in particular, 2,4,6-trisp-(2'-ethylhexyl-1'-oxycarbonyl)anilino!-1,3,5-triazine, sold under the trademark "Uvinul T 150" by BASF, have a high power for absorbing UV-B radiation. It would thus be very advantageous to be able to use those compounds in combination with 4-tert-butyl-4'-methoxydibenzoyl-methane for the purpose of obtaining products offering wide and effective protection throughout the full UV radiation range.
However, the inventors have observed that when these 1,3,5-triazine derivatives are in the presence of dibenzoylmethane derivatives, in particular, 4-tert-butyl-4'-methoxydibenzoylmethane, and under UV irradiation, they have the disadvantage of undergoing considerable chemical degradation. Under these conditions, the combination of two screening agents no longer allows broad, prolonged sunscreen protection for the skin and the hair.